the word 'tarantula' originates from the medieval latin 'tarantula', which itself derives from 'tarentum', the latin name for the southern italian city of taranto. the name was applied to a large wolf spider native to that region. historically, the bite of this spider was (erroneously) thought to cause a hysterical condition known as tarantism, which was believed to be curable only by frenzied dancing (the tarantella). over time, european explorers applied the name to larger, often more conspicuous hairy spiders encountered in the americas, which is its primary modern referent, shifting the term's association from a specific european spider to a broader family of new world theraphosid spiders.

the word is a loanword borrowed as a whole unit from italian. it is not productively formed from smaller, recognizable english morphemes.